So I'm on 64 bit Linuxmint 17 Cinnamon with Nvidia proprietary drivers 341.13.

When I'm scrolling a webpage or PDF in Firefox, my /usr/bin/X usage sky rockets and equals if not more then Firefox CPU usage. Combining them are using 100 percent CPU. Same thing happens when I'm watching a video on Smplayer. /usr/bin/X usage is a lot more then mplayer in the htop.

More accurately, it is this command which shots up from low CPU usage as displayed on htop

/usr/bin/X :0 -audit 0 -auth /var/lib/mdm/:0.Xauth -nolisten tcp vt8

Is there a way to reduce the resource hog?

Regards
batabuntu

i am guessing this isn't the newest machine? what is the cpu capable of?
which nvidia card exactly are you running, maybe there's some known issues?

what you can try:
- disable hardware rendering or acceleration in firefox settings
- install nouveau driver (read linux mint forums first on how to do that) and see if it helps.
- maybe, just maybe tell smplayer to use a different video output backend (not sure of the proper term here, it's in the settings)

how did you install the nvidia driver?

So I reverted back to Nouveau drivers. Firefox burning about 50CPU while Xorg 30CPU with "Cinnamon --replace" 11.

I have found the built-in PDF viewer in Firefox to have a few quirks myself.

Both Firefox 25 LTS and Firefox 30 under Slackware, when scrolling with the left navigation sidebar links or page view open eats 100% CPU on both 32 bit and 64 bit machines, Intel and Nvidia graphics. I played with it a bit and think it is a Firefox bug/quirk and have developed the habit of closing the left navigation sidebar when not in use.

I know this is not a fix, but it lets me use it without too much hassle. When reading larger PDF documents that I need to keep active, I open them in Ocular instead.

Hope this helps.